Defense Minister Daoud Rajiha during honoring officers of Syrian Army on the occasion of Army day celebrated in Damascus, Syria. According to the Syrian state television on July 18, 2012, Syrian defence minister was killed in an attack at national security building in Damascus.

Once he has ordered his security forces to exact a bloody revenge for the assassination of four key members of his inner circle in a spectacular bomb attack on the Syrian regime’s counterrevolutionary nerve center on Wednesday, President Bashar Assad will face the challenge of replacing those slain comrades. Not that his regime is a personality cult; it is the leadership of a sectarian system of authoritarian minority rule by a core of Alawites, supported by Christians and other smaller minorities, and a security and business elite drawn from the Sunni majority (which makes up the bulk of the rebellion). But by killing four of the key figures in security structure (curiously enough, they included two Alawites, a Christian and a Sunni) that has overseen the 18-month crackdown on the uprising that has claimed 16,000 lives, the rebels have struck a devastating blow at a critical moment — and challenged the regime’s coherence.

Syrian authorities now acknowledge that the bomb attack on the ad hoc security structure known in Damascus as the regime’s “crisis cell” for coordinating responses to the uprising was carried out by one of the guards assigned to the regime’s core decision makers. There were rival claims of responsibility from the Free Syrian Army and from an Islamist group. Still, the fact that the rebels’ reach extends into the room where the regime’s security chieftains are meeting will have sent a chilling message to Assad that can only fuel the paranoia and appetite for revenge by the regime. But its more immediate challenge will be replacing the key men lost in the blast:

Defense Minister Daoud Rajihah, 65, was an artillery specialist and an Orthodox Christian, a rarity in the regime’s security inner circle, and a key player in organizing the crackdown;

Assef Shawkat, the 62-year-old deputy defense minister, was an even closer Assad aide. A former head of military intelligence, he was implicated by the U.N. inquiry into the assassination of former Lebanon president Rafik Hariri. Shawkat was also married to President Assad’s sister, Bushra; and

Hassan Turkmani, the 77-year-old Sunni deputy Vice President and a former defense minister accused by rebels of orchestrating the torture campaign through which the regime initially tried to suppress the uprising. Turkmani was named in some reports as the head of the regime’s “crisis cell”.

Mohammed Ibrahim al-Shaar, the 62-year-old interior minister.
Of course there will be plenty of leaders willing to step up and replace those killed — the regime is held together by a widespread foreboding that a grim fate awaits them if Assad should fall–and that sense is shared not only among Alawite security men but also in the wider community from which they come. In the meantime, the regime is rapidly losing the Sunni elite without which it will be unable to govern all of Syria, even if it manages to remain intact.The defection of key Sunni figures associated with the regime such as Gen. Manaf Tlass and former ambassador Nawaf al-Fares has resulted in many others being placed under suspicion, forced to visit the security services and in many cases, having their passports seized. The regime is having to contend with a narrowing of its base even as its control over the capital is contested.Assad quickly named a new defense minister, Gen. Fahd Jassem al-Freij, who had coordinated special forces operations in Hama, Daraa and Idlib earlier in the uprising. But being forced to expand the circle of decision-makers will be a challenge to a regime whose sense of invulnerability will have been badly shaken by Wednesday’s blast. Developing a strategy to respond to the bad news from the battle front will prove even more challenging.

Tony Karon is a senior editor at TIME, where he has covered international conflicts in the Middle East, Asia, and the Balkans since 1997. A native of South Africa, he now resides with his family in Brooklyn, New York.

In practice, what exactly does that mean he does for a living? This article looks like it was written by a couple of confused interns. Or someone who thinks that just because a smartphone 'can' be used to create documents, it should.

Hey, can I be an editor too? It will be difficult, but I think over time I can master a writing style that veers from casual blog to serious-sounding journalism. Formatting, spelling, and other random errors will be thrown in gratis.

Does TIME's on-line division have an editor, or is the standard just assumed to be lower? Read the sub-headline ("In a severe low..."). Read the telegraphic caption. Read the first paragraph with run-on sentences that would make an 8th-grader blush.